Fire Flies goal? (possible slight spoiler)

So at the very begining of the game there is a news report about how the latest vaccine (sp?) had failed. I am ok with that however the FF's goal was to create a cure? Would that even be possible? Would that cure only work before the change happens? Did I just mis-understand what was being said or were they working toward a vaccine which to me makes a lot more sense.

Re: Fire Flies goal? (possible slight spoiler)

So at the very begining of the game there is a news report about how the latest vaccine (sp?) had failed. I am ok with that however the FF's goal was to create a cure? Would that even be possible? Would that cure only work before the change happens? Did I just mis-understand what was being said or were they working toward a vaccine which to me makes a lot more sense.

**spoilers**

The Fireflies goal was to liberate themselves from the oppressive grip of the Military, and yes they were working towards finding a cure. After learning of Ellie's ability (her mutation being like something they had never seen) they believed they could reverse engineer a vaccine. Whether or not this was true however, it appears we will never know. Obviously a vaccine would have to be given before the patient becomes infected, as that's how vaccines work. I don't think you could be cured from the major bodily damage of second third or fourth stages of infection.

As for the beginning of the game, I'm sure when the outbreak first started there were plenty of trial and error vaccines and anti fungals that turned out to be useless before the majority of the world finally gave up looking.